Need to Verify Model TSS Reduction Estimates

Transcription

1 Examples of Proprietary BMPs Using Settling for Treatment Modeling Manufactured Stormwater Control Practices Vortechs University of Wisconsin Madison Engineering Professional Development 1 DownStream Defender Benefits: Underground Easy to Install Easy Maintenance Need to Verify Model TSS Reduction Estimates Model Should Be Within 15 Percentage Points of the Measured Number Proprietary Device Monitoring - Rob Waschbusch 1

2 Manufacturer Sizing Guidelines Claimed 80% Removal of Total Suspended Solids for the Site Site Conditions Maintenance Yard 4.3 Acres with 100% Connected Imperviousness TM Monitoring Equipment Sampled 45 Runoff Events ( ) Monitoring Locations Bypass Sample Point Vortechs Partners: Inlet Sample Point Outlet Sample Point City of Milwaukee Milwaukee County Third Ward ETV Program WDNR USGS Manufacturers EPA Judy Horwatich, Peter Hughes, and Others 2

3 Milwaukee, WI. Test Site: I 794 Milwaukee, WI I 794 Site 18 Rain Events Vortechs Monitoring Site TSS Load Reduction Results Used for Model Comparison TSS Loads, lb. Type of Load Influent Effluent Vortechs (18 events, no bypass) (14 events, bypass) % TSS Reduction % % 3

4 Comparison of Monitored vs Modeled Water Volume, (cu ft) TSS Load, (lbs.) TM Measured Modeled % Diff. Measured Vortechs TM Modeled % Diff. 85,600 73, % 10,466 10,633-2 % % % Observed Versus Predicted Water Volumes and TSS Loads for Site Comparison of Measured and Modeled TSS Reductions Measured TSS Reductions SLAMM / DETPOND Estimates with Measured PSD and Rainfall 6% 12% Vortechs 25% 19% TSS Reduction, % TSS Reduction as a Function of Peak Discharge for the (includes both treated & bypass water) >1.1cfs = bypass flow Peak Flows, CFS 4

5 OVERALL TOTAL SUSPENDED SOLIDS AND SUSPENDED SEDIMENT CONCENTRATION REMOVAL, IN PERCENT Suspended sediment concentration Design Flow 1.6 cfs PEAK DISCHARGE, IN CUBIC FEET PER SECOND Total suspended solids EFFICIENCY FOR INDIVIDUAL EVENT, IN PERCENT I CONCENTRATION, IN MILLIGRAMS PER LITER (LOG SCALE) Suspended sediment concentration Total suspended solid Percent Greater Than Average Influent Particle Size Distributions for Vortechs and Sites Particle-size data used in WINSLAMM 80% Control 40% Control Vortech 62 Microns Particle size (Microns) Downstream Defender Hydro International Partners: Waukesha Group USGS NSF EPA City of Madison EarthTech Hydro International WDNR 5

6 Downstream Defender Study Site Madison Water Utility Bldg. (1.9 acres: 55% Parking Lot, 15% Lawn & 26% Roof Outlet to System Flow Splitter Inlet to Device Sampling Locations: 23 Events Sampled Between 2005 and 2006 Outlet 6

7 Inlet Samples Typical Samples For Study Site Outlet Samples Manufacturer s Claim For runoff at 15 C, the Downstream Defender will remove over 80% of settleable solids with a specific gravity of 2.65 with a particle size distribution similar to Maine DOT road sand at flow rates up to 3 cfs Hydro International defines settleable sediment as particles greater than 62 μm in size. ME Sand: Median = 700 microns Smallest = 70 microns 80% = Control All Particles > 300 microns Statistical Evaluation Between Inlet and Outlet Concentrations Constituents with Significant Difference SSC TSS Dissolved P Total Zinc Constituents Not Significantly Different Dissolved Copper Dissolved Zinc Total Copper Dissolved Solids Total P Constituent Sum of the Loads for Downstream Defender Total Suspended Solids Suspended Sediment Reduction for Device, % Reduction for System, % (7) (17) Diss. Phosphorus (11) Total Zinc (-3) ( ) = efficiency ratio 7

8 TSS Reduction as a Function of Peak Discharge TSS Sum of the Loads by Particle Size Percent TSS Reduction Design Flow Peak Discharge, cfs Particle Size Distribution for Solids Trapped in Bottom of Device Average PSD for DownStream Site & ME DOT Sand 300 microns 8

9 Overflow from Adjoining Drainage Area Berm to Block Flow Comparison of Inlet to Bypass Mean EMCs Outlet to System Flow Splitter Inlet to Device Outlet Location TSS SS TP Diss. P Zinc Inlet Bypass

10 Sum of the Loads for Three Hydrodynamic Separators Constituent Vortechnics Downstream Defender Total Suspended Solids Suspended Sediment NA Total Phosphorus 10 Insignificant 17 Total Zinc % Sand in Water NA Inlet TSS mg/l % Sand in Tank What Have We Learned: 1. No Changes to Technical Standard Stratification a problem over estimate reduction. 3. Increase Bypass Concentration 4. Devices Effective for > 250 micron 5. Effectiveness Range 0 to 25% TSS 6. Measuring PSD is very important 7. Devices very sensitive to flow changes Downstream Defender Vortechs Questions? University of Wisconsin Madison Engineering Professional Development 40 10